From 081dece1a3f2a4761f25cc27ebbb36d7a0fa950e Mon Sep 17 00:00:00 2001
From: henng <ruihenng@gmail.com>
Date: Sat, 12 Oct 2019 15:50:21 +0800
Subject: [PATCH] fixed 'bad access: nil dereference' when calling Error()
 method if itself is a nil reference.

---
 terror/terror.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/terror/terror.go b/terror/terror.go
index 91350dd72..b67304102 100644
--- a/terror/terror.go
+++ b/terror/terror.go
@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"strconv"
 
+	"github.com/modern-go/reflect2"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/mysql"
 	log "github.com/sirupsen/logrus"
@@ -213,10 +214,16 @@ func (e *Error) Location() (file string, line int) {
 
 // Error implements error interface.
 func (e *Error) Error() string {
+	if reflect2.IsNil(e) {
+		return "<nil>"
+	}
 	return fmt.Sprintf("[%s:%d]%s", e.class, e.code, e.getMsg())
 }
 
 func (e *Error) getMsg() string {
+	if reflect2.IsNil(e) {
+		return "<nil>"
+	}
 	if len(e.args) > 0 {
 		return fmt.Sprintf(e.message, e.args...)
 	}